.coupon {
    width: 300px;
     height: 100px;
     line-height: 100px;
     margin: 50px auto;
     text-align: center;
     position: relative;
     background: radial-gradient(circle at right bottom, transparent 10px, #ffffff 0) top right /50% 51px no-repeat,
     radial-gradient(circle at left bottom, transparent 10px, #ffffff 0) top left / 50% 51px no-repeat,
     radial-gradient(circle at right top, transparent 10px, #ffffff 0) bottom right / 50% 51px no-repeat,
     radial-gradient(circle at left top, transparent 10px, #ffffff 0) bottom left / 50% 51px no-repeat;
     filter: drop-shadow(2px 2px 2px rgba(0, 0, 0, .2));
   }
   .coupon span {
     display: inline-block;
     vertical-align: middle;
     margin-right: 10px;
     color: red;
     font-size: 50px;
     font-weight: 400;
   }